a- Choose System > Administration > Users and Groups from your Ubuntu menu.
b- Select the Group tab.
c- Click the 'Add Group' button
d- Name the group 'subversion'
e- Add yourself (for me username: bolat) and www-data (the Apache user) as users to this group
In order to see your user name and subversion group,
- Start gconf settings editor: Alt+F2 gconf-editor Enter.
- In the tree, locate /apps/gnome-system-tools/users.
- Select the "showall" check-box.